With machine made rugs there are several different types of synthetic materials that you may run into including: Polypropylene, olefin, nylon and rayon. What are these you may ask? These are all petroleum based products. In other words a form of plastic made too look and feel like wool, silk, or even grass. They are all 100% safe to use in you home sleep on and walk on. Since they are a plastic they are real not hard to uphold and clean as often as needed.